Method of manufacturing header tank for heat exchanger and heat exchanger having the header tank

ABSTRACT

A method of manufacturing a header tank for a heat exchanger includes forming a first engagement portion in a core plate, placing a tank body relative to a base portion of the core plate, and moving a first wall portion toward the tank body such that the first engagement portion is engaged with the tank body. In the forming, a portion of the core plate is bent, the portion extending from the first wall portion. In the placing, the tank body is placed such that an opening of the tank body is covered by the base portion such that a tank inner space is defined. The first engagement portion is engaged with the tank body by moving the first wall portion toward the tank body.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Applications No. 2006-321389 filed on Nov. 29, 2006 and No. 2007-104600 filed on Apr. 12, 2007, the disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method of manufacturing a header tank for a heat exchanger and a heat exchanger having the header tank.

BACKGROUND OF THE INVENTION

In general, a heat exchanger such as a radiator has tubes and a header tank. The header tank is, for example, constructed of a tank body having a semi-tubular shape and a core plate to which the tubes are coupled. The core plate is, for example, fixed to the tank body through engagement portions. A heat exchanger having such a structure is described in Japanese Unexamined Patent Publications No. 2004-66283 and No. 2002-286396 (U.S. Pat. No. 6,892,804), for example.

In the heat exchanger disclosed in the Publication No. 2004-66283, a core plate has a bottom wall portion, side wall portions extending from opposite ends of the bottom wall portion and engagement portions for engaging the core plate with a tank body. The core plate is connected to the tank body in the following manner. The tank body is arranged on the bottom wall portion of the core plate such that an opening of the tank body is covered by the bottom wall portion. Then, the side wall portions of the core plate are bent toward the tank body. Thereafter, the engagement portions are bent from the side wall portions toward the tank body. Thus, the core plate is fixed to the tank body by the engagement portions.

In such a heat exchanger, because pipe members, such as inlet pipe and outlet pipe, for introducing and discharging an internal fluid, are coupled to the tank body, the engagement portions will interfere in the pipe members during the bending of the side wall portions. In such a case, it will be difficult to properly bend the side wall portions toward the tank body. Also, if the tank body is provided with members such as fixing parts for fixing a fan shroud, the engagement portions will interfere in the members. Therefore, it will be difficult to properly bend the side wall portions toward the tank body.

FIG. 30 shows a header tank of the heat exchanger disclosed in the publication No. 2002-286396. A core plate 150 a is fixed to a tank body 150 b by bending engagement portions 1521. In this case, a thickness of the engagement portion 1521 is smaller than the other portions such as a side wall portion to reduce bending rigidity of the engagement portion 1521. Thus, the engagement portion 1521 can be bent toward the tank body 150 b by a relatively small force.

However, if an internal pressure of the header tank increases, the tank body 150 b receives the pressure in a direction oblique to a longitudinal direction D1 of the tubes, as shown by an arrow Ya. At this time, the engagement portion 1521 receives stress from a corner potion 1600 a of the tank body 150 b, as shown by an arrow Yb.

If the internal pressure of the header tank repetitively increases, the engagement portion 1521 repetitively receive the stress from the corner portion 1600 a. Since the decrease in the thickness of the engagement portion 1521 results in the decrease in the strength of the engagement portion 1521, the durability of the core plate 150 a reduces. Further, the durability of the heat exchanger will reduce.

SUMMARY OF THE INVENTION

The present invention is made in view of the foregoing matter, and it is an object of the present invention to provide a method of manufacturing a header tank for a heat exchanger, capable of improving assemblability, and a heat exchanger having the header tank manufactured by the method. It is another object of the present invention to provide a method of manufacturing a header tank for a heat exchanger, having sufficient durability, and a heat exchanger having the header tank manufactured by the method.

According to an aspect of the present invention, a method of manufacturing a header tank for a heat exchanger includes forming a first engagement portion in a core plate by bending a portion of the core plate, the portion extending from a first wall portion of the core plate and placing a tank body, which has a substantially semi-tubular shape and an opening, relative to a base portion of the core plate such that the opening is covered by the base portion and a tank inner space is provided between the tank body and the base portion. The method further includes moving the first wall portion toward the tank body such that the first engagement portion is engaged with the tank body.

Namely, the first engagement portion is formed in the core plate before the first wall portion is moved toward the tank body. Therefore, it is less likely that the first engagement portion will interfere with a component part such as a pipe member of the tank body when the first wall portion is moved toward the tank body. Accordingly, assemblability of the header tank improves.

For example, the first engagement portion is formed in the core plate, and then the first wall portion is bent along an edge of the base portion by a predetermined angle to be in a pre-bent condition. After the tank body is placed relative to the base portion, the first wall portion is moved from the pre-bent condition toward the tank body such that the first engagement portion engages with the tank body.

As another example, the first engagement portion is formed on the core plate, and a portion of the first wall portion is bent outwardly along a bending axis with the first engagement portion to be in a pre-bent condition. After the tank body is placed on the base portion, the portion of the first wall portion is moved toward the tank body about the bending axis such that the first engagement portion engages with the tank body. In this case, the bending axis is included within the first wall portion, and the portion of the first engagement portion is moved toward the tank body to engage the first engagement portion with the tank body about the bending axis. Thus, it is not necessary to form a weak portion, at which a strength is reduced for easing bending, on a corner portion between the first wall portion and the first engagement portion. Because the strength of the corner portion is not reduced, the core plate maintains durability even if the corner portion receives stress from the tank body due to an increase in an internal pressure of the header tank. Accordingly, the header tank maintains sufficient durability.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which like parts are designated by like reference numbers and in which:

FIG. 1 is a schematic plan view of a radiator according to a first embodiment of the present invention;

FIG. 2 is a cross-sectional view of the radiator taken along a line II-II in FIG. 1;

FIG. 3 is an enlarged view of a part of the radiator denoted by a dashed line III in FIG. 1;

FIG. 4 is an enlarged view of a part of the radiator denoted by a dashed line IV in FIG. 1;

FIG. 5A is a plan view of a core plate of the radiator according to the first embodiment;

FIG. 5B is an end view of the core plate according to the first embodiment;

FIG. 6 is a schematic cross-sectional view of the core plate taken along a line VI-VI in FIG. 5A;

FIG. 7 is a flow chart showing a manufacturing process of the radiator according to the first embodiment;

FIG. 8A to 8D are schematic views for showing steps of the manufacturing process according to the first embodiment;

FIG. 9 is a perspective view of a header tank of the radiator for showing side walls and engagement portions of the core plate according to the first embodiment;

FIGS. 10A to 10D are schematic views for showing steps of the manufacturing process according to the first embodiment;

FIG. 11 is a schematic cross-sectional view of a header tank of a radiator of a comparative example;

FIG. 12 is a schematic perspective view of a header tank of a radiator according to a second embodiment of the present invention;

FIG. 13A is a plan view of a core plate of the header tank according to the second embodiment;

FIG. 13B is an end view of the core plate according to the second embodiment;

FIG. 14 is a schematic perspective view of the header tank according to the second embodiment of the present invention;

FIG. 15 is a schematic cross-sectional view of a connecting portion between a core plate and a tank body of a radiator according to a third embodiment of the present invention;

FIG. 16 is a schematic cross-sectional view of a connecting portion between a core plate and a tank body of a radiator according to a fourth embodiment of the present invention;

FIG. 17 is a schematic cross-sectional view of a part of a tank body and a part of a core plate of a radiator according to a fifth embodiment of the present invention;

FIG. 18 is a cross-sectional view of a header tank of a radiator according to a sixth embodiment of the present invention;

FIG. 19 is a schematic perspective view of the header tank, partly including a cross-section, according to the sixth embodiment;

FIG. 20 is a cross-sectional view of a part of the header tank denoted by a dashed line XX in FIG. 19;

FIG. 21 is a perspective view of the header tank according to the sixth embodiment;

FIG. 22A is a plan view of a core plate of the header tank according to the sixth embodiment;

FIG. 22B is an end view of the core plate according to the sixth embodiment;

FIG. 23 is a flow chart showing a manufacturing process of the radiator according to the sixth embodiment;

FIGS. 24 to 26 are schematic views for showing steps of the manufacturing process according to the sixth embodiment;

FIG. 27 is a cross-sectional view of a header tank of a radiator according to a seventh embodiment of the present invention;

FIGS. 28 and 29 are schematic views for showing steps of a manufacturing process of the radiator according to the seventh embodiment; and

FIG. 30 is a schematic cross-sectional view of a header tank of a heat exchanger of a prior art.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereafter, first to seventh embodiments of the present invention will be described with reference to the accompanying drawings. In the second to seventh embodiments, components similar to those of the first embodiment will be indicated by the same numerals and will not be described further.

First Embodiment

FIG. 1 shows a heat exchanger 1 of the first embodiment when viewed along a flow direction of air. The heat exchanger 1 is exemplarily employed to a radiator that is generally mounted in an engine compartment of a vehicle and performs heat exchange between an engine coolant and the air, the flow of which is for example generated by a blower, thereby to cool the engine coolant.

The radiator 1 generally includes tubes 2, fins 3, side plates 4 a, 4 b and header tanks 5 a, 5 b. The tubes 2 have generally flat tubular shapes, and form passages therein for allowing the engine coolant, which flows out from the engine, to pass through. The tubes 2 are, for example, made of light metals having high heat conductivity. In the present embodiment, the tubes 2 are exemplarily made of aluminum alloy. Also, the tubes 2 are formed of clad members, at least one of surfaces of which is coated with a filler material, such as a brazing material.

The fins 3 are joined to outer surfaces of the tubes 2 to increase heat transfer area with the air, thereby to facilitate the heat exchange between the air and the engine coolant. The fins 3 are, for example, corrugate fins having wave forms when viewed along the flow direction of the air. The corrugate fins are shaped by roller-forming, for example. The fins 3 and the tubes 2 are alternately stacked. The stack of the fins 3 and tubes 2 has a generally rectangular parallelepiped shape and provides a core part 4.

The side plates 4 a, 4 b are located at the ends of the core part 4, as reinforcement members for reinforcing the core part 4. The side plates 4 a, 4 b extend in a longitudinal direction D1 of the tubes 2 (hereafter, the tube longitudinal direction D1). For example, the side plates 4 a, 4 b are made of light metals, such as aluminum alloy.

The header tanks 5 a, 5 b are located at longitudinal ends of the tubes 2, and in communication with the tubes 2. The header tanks 5 a, 5 b extend in a tube stacking direction that is perpendicular to the tube longitudinal direction D1.

An inlet pipe 6 a is coupled to the header tank 5 a. The inlet pipe 6 a is in communication with an engine coolant circuit on a downstream side of the engine for introducing the engine coolant, which flows out from the engine with a high temperature, into the header tank 5 a. An outlet pipe 6 b is coupled to the header tank 5 b. The outlet pipe 6 b is in communication with the engine coolant circuit on an upstream side of the engine for returning the engine coolant having passed through the radiator 1 toward the engine. Thus, the header tank 5 a serves as an inlet header tank for distributing the engine coolant into the tubes 2, and the header tank 5 b serves as an outlet header tank for collecting the engine coolant, which has passed through the tubes 2, therein and returning the engine coolant toward the engine coolant circuit.

In the present embodiment, the header tank 5 a and the header tank 5 b have the substantially similar structure, other than the inlet and outlet pipes 6 a, 6 b. Therefore, a structure of the header tank 5 a will be described in detail hereafter, as an example.

Referring to FIGS. 2 and 3, the header tank 5 a generally includes a core plate 50 a and a tank body 50 b. The tank body 50 b forms a tank inner space 50 c therein with the core plate 50 a.

The tank body 50 b is, for example made of a resin. As shown in FIG. 3, the tank body 50 b has a generally semi-tubular shape defining a longitudinal axis in the tube stacking direction. As shown in FIG. 4, the tank body 50 b has end walls 500 at longitudinal ends of the semi-tubular body.

The tank body 50 b has a projected end 600 along a perimeter of an opening of the semi-tubular body. The projected end 600 projects in directions perpendicular to the tube longitudinal direction D1, that is, project in a tank longitudinal direction (lengthwise direction) D2 and a tank transverse direction (widthwise direction) D3. Also, the projected end 600 is formed into a generally loop shape to surround the tank inner space 50 c. Here, the tank longitudinal direction D2 is parallel to the longitudinal axis of the tank body 50 b. Also, the tank longitudinal direction D2 is parallel to the tube stacking direction. The tank transverse direction D3 is perpendicular to the tube longitudinal direction D1 and the tank longitudinal direction D2.

The core plate 50 a is, for example, made of aluminum alloy. The core plate 50 a has a bottom wall portion (base portion) 51 and side wall portions (wall portions) 52 a, 52 b. The bottom wall portion 51 has a substantially rectangular plate shape, and extends in the tank longitudinal direction D2. The bottom wall portion 51 is configured to cover the opening of the semi-tubular-shaped tank body 50 b, thereby to form the tank inner space 50 c with the tank body 50 b.

The side wall portions 52 a, 52 b are disposed at opposite sides of the bottom wall portion 51 with respect to the tank transverse direction D3. That is, the side wall portions 52 a, 52 b extend from lengthwise edges of the rectangular-shaped bottom wall portion 51 in the tube longitudinal direction D1, the lengthwise edges being parallel to the tank longitudinal direction D2.

In FIG. 2, the side wall portion 52 a is disposed outside of a left portion of the projected end 600, and the side wall portion 52 b is disposed outside of a right portion of the projected end 600. Namely, the side wall portions 52 a, 52 b extend along outer surfaces of the projected end 600.

The core plate 50 a has side engagement portions (lip portions) 53 a, 53 b. The side engagement portions 53 a, 53 b project from ends of the side wall portions 52 a, 52 b, respectively, toward the tank body 50 b. Each of the side engagement portions 53 a, 53 b extends over the length of the side wall portion 52 a, 52 b in the tank longitudinal direction D2.

As shown in FIG. 4, the core plate 50 a further has end wall portions (wall portions) 52 c, 52 d and end engagement portions (end engagement pieces) 53 c, 53 d. In FIG. 4, the end wall portion 52 c and the end engagement portions 53 c are exemplarily illustrated, but the end wall portion 52 d and the end engagement portions 53 d are not illustrated since the end wall portion 52 d and the end engagement portion 53 d respectively have similar structures as the end wall portion 52 c and the end engagement portion 53 c.

The end wall portions 52 c, 52 d are located at the longitudinal ends of the bottom wall portion 51. That is, the end wall portions 52 c, 52 d extend from widthwise edges of the bottom wall portion 51 toward the tank body 50 b, such as, in the same direction as the side wall portions 52 a, 52 b, the widthwise edges being perpendicular to the longitudinal axis of the tank body 50 b.

The end wall portions 52 c, 52 d are disposed outside of the projected end 600 of the tank body 50 b. As shown in FIG. 4, the end wall portions 52 c, 52 d are formed separately from the side wall portions 52 a, 52 b. The end engagement portions 53 c, 53 d project from the end wall portions 52 c, 52 d toward the tank body 50 b.

As shown in FIG. 5A, the bottom wall portion 51 is formed with first through holes 56. The first through holes 56 are aligned in the tank longitudinal direction D2. As shown in FIGS. 5A and 6, the first through holes 56 are formed so as to join the core plate 50 a with the tubes 2 and the side plates 4 a, 4 b.

The bottom wall portion 51 has a looped flat section 57 providing a sealing surface. The looped flat section 57 is disposed to surround the first through holes 56 in the form of loop, as shown by dashed line E in FIG. 5A.

The bottom wall portion 51 is further formed with ribs 70 that project from the looped flat section 57 toward the tank inner space 50 c. The ribs 70 are aligned in the tank longitudinal direction D2. The first through holes 56 are formed at the top ends of the ribs 70, respectively. Also, the bottom wall portion 51 is formed with projections 71 between the ribs 70. Each of the projections 71 is disposed between two of the ribs 70, and projects from the looped flat section 57 in the direction opposite to the tank inner space 50 c, that is, in the direction opposite to the ribs 70.

Also, the bottom wall portion 51 is formed with second through holes 58, as shown in FIG. 5A. The second through holes 58 are formed on opposite sides of the through holes 56 with respect to the tank transverse direction D3. The second through holes 58 are arranged in lines in the tank longitudinal direction D2 for providing weak portions at which strength is reduced smaller than the other portions on the core plate 50 a. In other words, the second through holes 58 provide bending base portions for bending the side wall portions 52 a, 52 b relative to the bottom wall portion 51.

That is, the second through holes 58 are formed along bending axes of the side wall portions 52 a, 52 b so as to provide the weak portions. The side wall portions 52 a, 52 b are easily bent along the bending axes.

The core plate 50 a is made of a clad member having a clad surface cladded with a filler material, such as a brazing material. That is, the surface of the core plate 50 a to which the tubes 2 are inserted is previously coated with the filler material. The side plates 4 a, 4 b are made of clad members having clad surfaces cladded with a filler material, such as a brazing material. That is, the surfaces of the side plates 4 a, 46 that contact the tubes 2 are coated with the filler material.

As shown in FIGS. 2 and 3, a sealing member 54 is interposed between the looped flat section 57 of the bottom wall portion 51 and the projected end 600 of the tank body 50 b for sealing between the tank body 50 b and the core plate 50 a. In other words, the sealing member 54 is provided to restrict the engine coolant from leaking from the tank inner space 50 c.

In the present embodiment, the sealing member 54 is formed by hardening a liquid or gel sealing material. For example, the sealing material is an acrylic resin that is hardened by ultraviolet rays. The sealing member 54 can be provided by a resin having durability against an antifreeze solution. Further, the sealing material is not limited to the ultraviolet curing resin, but can be another material, such as a thermosetting resin that is hardened by heat.

Next, a method of manufacturing the radiator 1 will be described with reference to FIGS. 7 to 10. FIG. 7 shows a process of manufacturing the radiator 1.

At step S100, component parts, such as the tubes 2, the core plates 50 a, the fins 3, the side plates 4 a, 4 b, are prepared. Each of the core plate 50 a is formed in a manner shown in FIGS. 8A to 8D. First, a plate member 100, which is made of aluminum alloy, is prepared, as shown in FIG. 8A. The plate member 100 includes a base wall corresponding to the bottom wall portion 51, the flaps corresponding to the wall portions 52 a, 52 b, 52 c, 52 d, and portions corresponding to the engagement portions 53 a, 53 b, 53 c, 53 d.

The first and second through holes 56, 58 are formed on the plate member 100, as shown in FIG. 8B. Next, the portions corresponding to the side engagement portions 53 a, 53 b are bent perpendicular to the flaps corresponding to the side wall portions 52 a, 52 b so that the side engagement portions 53 a, 53 b are formed, as shown in FIG. 8C.

Thereafter, the flaps corresponding to the side wall portions 52 a, 52 b are bent at a predetermined angle θ with respect to a plane of the base wall to be in a pre-bent condition. Here, the predetermined angle θ is smaller than 90 degrees.

Next, the other flaps of the plate member 100, which correspond to the end wall portions 52 c, 52 d, are bent substantially perpendicular to the base wall portion 51. At this time, the portions corresponding to the end engagement portions 53 c, 53 d have not been bent relative to the flaps corresponding to the end wall portions 52 c, 52 d, yet.

At step S110, the core part 4 is assembled. For example, the tubes 2 are arranged at predetermined intervals, and the fins 3 are placed between the tubes 2, so that the core part 4 is preliminarily assembled. Next, the ends of the tubes 2 and the ends of the side plates 4 a, 4 b are inserted into the first through holes 56 of the core plates 50 a, which is for one of the header tanks 5 a, 5 b. At this time, the ends of the tubes 2 are inserted up to positions corresponding to the tank inner space 50 c.

Then, the ends of the tubes 2 are expanded by pipe expanding. That is, the ends of the tubes 2 are processed such that inner diameter thereof increases. As such, the tubes 2 are preliminarily fixed to the core plate 50 a.

Also, opposite ends of the tubes 2 and opposite ends of the side plates 4 a, 4 b are inserted into the first through holes 56 of another core plate 50 a, which is for the other one of the header tanks 5 a, 5 b. The opposite ends of the tubes 2 are expanded by pipe expanding. Thus, the tubes 2 and the core plate 50 a are preliminarily fixed.

In this way, the core plates 50 a of the header tanks 5 a, 5 b, the tubes 2, the fins 3 and the side plates 4 a, 4 b are preliminarily fixed together. Then, the preliminarily fixed members 2, 3, 4 a, 4 b, 50 a are held in the condition by a jig and heated in a furnace. Accordingly, the tubes 2, the fins 3, the side plates 4 a, 4 b and the core plates 5 a, 5 b are integrally joined by brazing.

At step S121, the sealing material in a liquid or gel state is applied to the looped flat sections 57 of the core plates 50 a, and ultraviolet rays are radiated to the applied sealing material for hardening the sealing material.

At step S122, the tank body 50 b is placed on each core plate 50 a, so that the opening of the tank body 50 b is covered by the bottom wall potion 51 of the core plate 50 a and the tank inner space 50 c is provided, as shown in FIG. 9. In this condition, the side wall portions 52 a, 52 b of each core plate 50 a are inclined at the predetermined angle θ relative to the plane of the bottom wall portion 51, as shown in FIGS. 9 and 10A. Also, the engagement portions 53 a, 53 b are perpendicular to the side wall portions 52 a, 52 b, and the end wall portions 52 c, 52 d are substantially perpendicular to the bottom wall portion 51.

At step S123, the tank body 50 b is held on the core plate 50 a in the tube longitudinal direction D1 by a jig, as shown by an arrow F of FIG. 10B.

At step S124, the side engagement portions 53 c, 53 d are engaged with the projected end 600. For example, the side engagement portions 53 c are bent relative to the end wall portion 52 c toward the tank body 50 b by applying forces as shown by arrows H in FIG. 9. Likewise, the end engagement potions 53 d are bent relative to the end wall portion 52 d toward the tank body 50 b.

As such, the projected end 600 of the tank body 50 b is engaged with the end engagement portions 53 c, 53 d. In this condition, the sealing member 54 is held between the projected end 600 of the tank body 50 b and the looped flat section 57 of the core plate 50 a, as shown in FIG. 4.

At step S125, the side engagement portions 53 a, 53 b are engaged. Specifically, the side wall portions 52 a, 52 b are further bent toward the tank body 50 b from the pre-bent condition by applying forces as shown by an arrow G in FIG. 10B, so that the side engagement portions 53 a, 53 b are engaged with the projected end 600.

As such, as shown in FIG. 10C, the projected end 600 of the tank body 50 b and the sealing member 54 are held between the looped flat section 57 of the core plate 50 a and the side engagement portions 53 a, 53 b. In other words, the projected end 600 of the tank body 50 b is engaged with the side engagement portions 53 a, 53 b.

At step S126, the jig that is holding the tank body 50 b is released from the tank body 50 b. In this way, the header tank 5 a is formed. The header tank 5 b is formed in the similar manner as the header tank 5 a.

In the present embodiment, the core plate 50 a in which the side engagement portions 53 a, 53 b are already formed is prepared. That is, the side engagement portions 53 a, 53 b are bent relative to the side wall portions 52 a, 52 b before the tank body 50 b is placed on the core plate 50 a. After the tank body 50 b is placed on the core plate 50 a, the side wall portions 52 a, 52 b are moved toward the projected end 600 of the tank body 50 b. As such, the projected end 600 of the tank body 50 b is engaged by the side engagement portions 53 a, 53 b. In other words, the side engagement portions 53 a, 53 b are previously bent, and are engaged with the projected end 600 by moving the side wall portions 52 a, 52 b toward the tank body 50 b.

FIG. 11 shows another method of forming a header tank, as a comparative example. In FIG. 11, the side engagement portions 53 a, 53 b are bent after the side wall portions 52 a, 52 b are bent toward the tank body 50 b relative to the bottom wall portion 51. In this case, the engagement portions 53 a, 53 b will interfere with the pipe 6 a, 6 b. Therefore, it is difficult to properly bend the side engagement portions 53 a, 53 b. In addition, if a distance between the pipe 6 a, 6 b and the projected end 600 of the tank body 50 b is insufficient for inserting a jig for crimping, it is difficult to properly bend the side engagement portions 53 a, 53 b.

In the comparative example shown in FIG. 11, the distance between the pipes 6 a, 6 b and the projected end 600 can be increased by arranging the pipes 6 a, 6 b at positions further from the bottom wall portion 51. In this case, however, a height of the tank body 50 b, that is, a dimension of the tank body 50 b in the tube longitudinal direction D1 needs to be increased.

In the present embodiment, on the other hand, the core plate 50 a in which the side engagement portions 53 a, 53 b are previously bent is used. In other words, the side engagement portions 53 a, 53 b are bent before the side wall portions 52 a, 52 b are completely bent toward the projected end 600. Therefore, it is less likely that the side engagement portions 53 a, 53 b will interfere with the pipe 6 a, 6 b when the side engagement portions 53 a, 53 b are engaged with the projected end 600. Accordingly, assemblability improves.

Also, it is not necessary to insert the jig between the pipe 6 a, 6 b and the projected end 600 of the tank body 50 b for bending the side engagement portions 53 a, 53 b. Therefore, it is not necessary to increase the height of the tank body 50 b, that is, the dimension in the tube longitudinal direction D1, as the comparative example.

Further, the core plate 50 a in which the side wall portions 52 a, 52 b are previously bent at the predetermined angle θ relative to the bottom wall portion 51 before the placing of the tank body 50 b is used. That is, the side wall portions 52 a, 52 b have been already bent at the predetermined angle θ relative to the bottom wall portion 51 before the tank body 50 b is placed on the core plate 50 a. Therefore, the side wall portions 52 a, 52 b are easily moved toward the projected end 600 even after the tank body 50 b is placed on the core plate 50 a.

The second through holes 58 are formed on the core plate 50 a along the bending axes of the side wall portions 52 a, 52 b, as the weak portions. Therefore, the side wall portions 52 a, 52 b are easily bent. Since the second through holes 58 are located outside of the tank inner space 50 c with respect to the sealing member 54, it is less likely that the coolant will leak from the second through holes 58.

The sealing member 54 is provided by applying the liquid or gel state sealing material to the looped flat section 57 of the core plate 50 a and hardening the sealing material. The sealing member 54 maintains adhesion properties even after the hardened. The sealing member 54 is in closely contact with the looped flat section 57 of the core plate 50 a by the adhesion properties. Therefore, it is less likely that the sealing member 54 will be twisted or displaced.

The sealing member 54 is held between the looped flat section 57 of the core plate 50 a and the projected end 600 of the tank body 50 b in an elastically deformed condition. Therefore, the looped flat section 57 and the projected end 600 are effectively sealed by the sealing member 54. Accordingly, it is less likely that the coolant will leak from the header tanks 5 a, 5 b.

In the present embodiment, since the bottom wall portion 51 has the projections 71, the rigidity of the bottom wall portion 51 against the bending is improved. Therefore, even if the load is applied to the bottom wall portion 51, such as when bending the side wall portions 52 a, 52 b, the bottom wall portion 51 will not be easily deformed.

In the above discussion, the sealing material is applied to the sealing surface of the looped flat section 57 of the core plate 50 a. Alternatively, the sealing material can be applied to the projected end 600 of the tank body 50 b.

Instead of forming the second through holes 58 on the core plate 50 a, grooves or recesses can be formed as the weak portions. For example, grooves or recesses having V-shaped cross-section or U-shaped cross-section may be formed to provide the weak portions. Also, it is not always necessary to form the grooves or recesses continuously in the tank longitudinal direction D2. The grooves or recesses may be formed discontinuously in the tank longitudinal direction D2. The weak portions may be also formed along bending axes of the end wall portions 52 c, 52 d.

In the above discussion, the side engagement portions 53 a, 53 b are previously bent relative to the side wall portions 52 a, 52 b. In addition to this or alternatively, the end engagement portions 53 c, 53 d can be previously bent relative to the end wall portions 52 c, 52 d, in a similar manner as the side engagement portions 53 a, 53 b. Also, the end wall portions 52 c, 52 d may be bent in a similar manner as the side wall portions 52 a, 52 b.

Second Embodiment

In the radiator 1 of the second embodiment, the core plate 50 a has a shape slightly different from the core plate 50 a of the radiator 1 of the first embodiment.

In a case that the tank body 50 b and the core plate 50 a are made of different materials, such as aluminum alloy and resin, the tank body 50 b has a coefficient of linear expansion greater than that of the core plate 50 a. Under a high temperature condition, the end wall portions 52 c, 52 d will be deformed by being pressed by the projected end 600 in the tank longitudinal direction D2 due to thermal expansion of the tank body 50 b.

In the second embodiment, therefore, the core plate 50 a includes support wall portions 610 for supporting the end wall portions 52 c, 52 d, as shown in FIGS. 12, 13A and 13B. The support wall portions 610 project from the lengthwise edges of the bottom wall portion 51, at positions adjacent to the longitudinal ends of the core plate 50 a. In addition, the support wall portions 610 connect to the end wall portions 52 c, 52 d. The support wall portions 610 are separated from the side wall portions 52 a, 52 b.

Therefore, even if the end wall portions 52 c, 52 d are pressed due to the expansion of the tank body 50 b, each of the end wall portions 52 c, 52 d is supported by two support wall portions 610. As such, the deformation of the end wall portions 52 c, 52 d due to the expansion of the tank body 50 b is reduced.

Also in the present embodiment, the side engagement portions 53 a, 53 b are previously bent relative to the side wall portions 52 a, 52 b, as shown in FIG. 14, similar to the first embodiment. Accordingly, the similar effects as the first embodiment will also be provided.

Third Embodiment

In the core plate 50 a of the radiator 1 of the first embodiment, each of the side engagement portions 53 a, 53 b forms a generally right angle with the corresponding side wall portion 52 a, 52 b, as shown in FIG. 2. However, the angle between the side engagement portion 53 a, 53 b and the side wall portion 52 a, 52 b can be modified.

In the radiator 1 of the third embodiment, each side engagement portion 53 a, 53 b is engaged with the projected end 600 such that an angle +1 between the side engagement portion 53 a, 53 b and the side wall portion 52 a, 52 b is smaller than 90 degrees, as shown in FIG. 15. Therefore, an engagement force, that is, a force for joining the tank body 50 b with the core plate 50 a improves. Further, the sealing effect of the sealing member 54 improves.

The above engagement structure may be also employed to the end engagement portions 53 c, 53 d. That is, the end engagement portions 53 c, 53 d may be engaged with the projected end 600 such that the angle between the end engagement portion 53 c, 53 d and the end wall portion 52 c, 52 d is smaller than 90 degrees, similar to the side engagement portions 53 a, 53 b.

Fourth Embodiment

In the radiator 1 of the first embodiment, each of the side wall portions 52 a, 52 b of the core plate 50 a forms a generally right angle with the bottom wall portion 51, as shown in FIG. 2. However, the angle between the side wall portion 52 a, 52 b and the bottom wall portion 51 can be modified.

In the radiator. 1 of the fourth embodiment, the side wall portions 52 a, 52 b are bent more than 90 degrees relative to the plane of the bottom wall portion 51. That is, the angle 42 defined between the outer surface of each side wall portion 52 a, 52 b and the plane of the bottom wall portion 51 is more than 90 degrees. Accordingly, the force for joining the tank body 50 b and the core plate 50 a improves.

The above bending structure may be also employed to the end wall portions 53 a, 53 b. That is, the end wall portions 52 c, 52 d may be bent more than 90 degrees relative to the plane of the bottom wall portion 51, similar the side wall portions 52 a, 52 b.

Fifth Embodiment

In the radiator 1 of the first embodiment, the core plate 50 a has the looped flat section 57 on the bottom wall portion 51. The sealing material for the sealing member 54 is applied to the looped flat section 57. In the radiator 1 of the fifth embodiment, the bottom wall portion 51 is formed with a sealing groove 57 a, as shown in FIG. 17, and the sealing material for the sealing member 54 is applied in the groove 57 a. For example, the groove 57a is formed such that the flat wall section 57 corresponds to the bottom of the groove 57 a.

Therefore, the sealing member 54 is effectively positioned relative to the core plate 50 a. Also in the present embodiment, the side engagement portions 53 a, 53 b are previously bent relative to the side wall portions 52 a, 52 b. Further, the end engagement portions 52 c, 52 d may be bent relative to the end wall portions 52 c, 52 d before the end wall portions 52 c, 52 d are bent toward the tank body 50 b.

Sixth Embodiment

The radiator 1 of the sixth embodiment has the core plate 50 a shown in FIGS. 18 to 22B. In the sixth embodiment, the side wall portions 52 a, 52 b have side grooves 520 a, 520 b as the weak portions, instead of the second through holes 58 of the above embodiments. Structures other than the core plate 50 a are similar to those of any one of the above embodiments.

The side grooves 520 a, 520 b are formed on outer surfaces of the side wall portions 52 a, 52 b. The side grooves 520 a, 520 b extend over the length of the side wall portions 52 a, 52 b in the tank longitudinal direction D2. In the side wall portions 52 a, 52 b, portions corresponding to the side grooves 520 a, 520 b have strength less than the remaining portions of the side wall portions 52 a, 52 b. The side grooves 520 a, 520 b provide the bending base portions along which the side wall portions 52 a, 52 b are bent toward the tank body 50 b.

The projected end 600 of the tank body 50 b projects toward the side grooves 520 a, 520 b from the inside of the core plate 50 a, and contacts the side wall portions 52 a, 52 b. Also, the projected end 600 partly projects toward the bottom wall portion 51, as shown in FIG. 20. That is, a portion 601 of the projected end 600, such as an outer peripheral portion of the projected end 600, protrudes toward the bottom wall portion 51 such that the projected end 600 sufficiently contacts the weak portions of the side wall portion 52 a, 52 b at which the strength is reduced by the side grooves 520 a, 520 b. In the example shown in FIG. 20, a lower surface of the projected end 600 partly protrudes toward the bottom wall portion 51. In other words, the weak portions provided by the side grooves 520 a, 520 b are located at positions corresponding to the projected end 600 of the tank body 50 b.

Also in the present embodiment, the core plate 50 a has the side engagement portions 53 a, 53 b, similar to the side engagement portions 53 a, 53 b of any one of the above embodiments. Also, the core plate 50 a has the end wall portions 52 c, 52 d and the end engagement portions 53 c, 53d, similar to the end wall portions 52 c, 52 d and the end engagement portions 53 c, 53 d of any one of the above embodiments.

The bottom wall portion 51 has the ribs 70 and the projections 71, similar to the example shown in FIG. 6. The first through holes 56 are formed on the top ends of the ribs 70. In the present embodiment, each of the projections 71 has a width W2 greater than a width W1 of each tube 2 with respect to the tank transverse direction D3, as shown in FIG. 26. The ribs 70 and the projections 71 are formed by pressing or punching, for example.

Next, a method of manufacturing the radiator 1 of the present embodiment will be described with reference to FIGS. 23 to 26.

First, at a step S200, component parts, such as the tubes 2, the core plates 50 a, the fins 3, and the side plates 4 a, 4 b, are prepared. Regarding the core plate 50 a, the side engagement portions 53 a, 53 b and portions 525 a, 525 b of the side wall portions 52 a, 52 b, which are adjacent to the side engagement portions 53 a, 53 b are shaped as shown in FIG. 24. Hereafter, the portions 525 a, 525 b are referred to as engagement portion-side sections 525 a, 525 b. The engagement portion-side sections 525 a, 525 b are bent outwardly along the side grooves 520 a, 520 b. The side engagement portion 53 a, 53 b are bent relative to the engagement portion-side sections 525 a, 525 b.

At a step S210, the core part 4 is assembled. For example, the tubes 2 are arranged at predetermined intervals, and the fins 3 are interposed between the tubes 2, so that the core part 4 is preliminarily assembled. Then, the ends of the tubes 2 and the ends of the side plates 4 a, 4 b are inserted into the first through holes 56 of the core plate 50 a, which is for one of the header tanks 5 a, 5 b.

Then, the ends of the tubes 2, which are inserted up to positions corresponding to the tank inner space 50 c, are expanded by pipe expanding. That is, the ends of the tubes 2 are expanded such that the inner diameter thereof are increased, so that the tubes 2 are preliminarily fixed to the core plate 50 a.

Also, opposite ends of the tubes 2 and opposite ends of the side plates 4 a, 4 b are inserted to the first through holes 56 of another core plate 50 a, which is for the other one of the header tanks 5 a, 5 b. The opposite ends of the tubes 2 are also expanded by pipe expanding. Thus, the opposite ends of the tubes 2 are preliminarily fixed to the core plate 50 a.

Accordingly, the core plates 50 a of the header tanks 5 a, 5 b, the tubes 2, the fins 3 and the side plates 4 a, 4 b are preliminarily fixed.

Also at the step S210, the preliminarily fixed body is held in this condition by a jig and heated in a furnace. Thus, the tubes 2, the fins 3, the side plates 4 a, 4 b and the core plates 50 a are integrally joined by brazing.

At a step S220, the sealing material in the gel or liquid state is applied to the looped flat section 57 of the core plate 50 a, and the ultraviolet rays are radiated to the sealing material for hardening, as shown in FIG. 25.

At a step S230, the tank body 50 b is placed on the core plate 50 a such that the opening of the tank body 50 b is covered by the bottom wall portion 51. In this condition, the engagement portion-side sections 525 a, 525 b are still expanded in the outward direction. Also, the side engagement portions 53 a, 53 b are substantially perpendicular to the engagement portion-side sections 525 a, 525 b, as shown in FIGS. 25 and 26.

At a step S240, forces are applied to the engagement portion-side sections 525 a, 525 b as shown by arrows J in FIG. 25, so that the engagement portion-side sections 525 a, 525 b are bent toward the tank body 50 b along the side grooves 520 a, 520 b as the bending axes. That is, the engagement portion-side sections 525 a, 525 b are bent toward the tank body 50 b by plastically deforming the portions where the grooves 520 a, 520 b are formed.

Therefore, the side wall portions 52 a, 52 b become flat or straight in the direction perpendicular to the bottom wall portion 51, that is, in the tube longitudinal direction D1, and the side engagement portions 53 a, 53 b are engaged with the projected end 600 of the tank body 50 b.

That is, as shown in FIG. 26, the tank body 50 b and the core plate 50 a are fixed to each other in a manner that the projected end 600 and the sealing member 54 are disposed between the side engagement portions 53 a, 53 b and the bottom wall portion 51.

The end wall portions 52 c, 52 d are previously bent substantially perpendicular to the bottom wall portion 51. The end engagement portions 53 c, 53 d are bent toward the tank body 50 b and perpendicular to the end engagement portions 52 c, 52 d, after the tank body 50 b is placed on the core plate 50 a. Thus, the end engagement portions 53 c, 53 d engage the projected end 600 of the tank body 50 b.

Namely, the tank body 50 b and the core plate 50 a are fixed also by engaging the end engagement portions 53 c, 53 d with the projected end 600. The end engagement portions 53 c, 53 d engage with the projected end 600 such that the projected end 600 and the sealing member 54 are disposed between the end engagement portions 53 c, 53 d and the bottom wall portion 51.

In the present embodiment, the side wall portions 52 a, 52 b have the side grooves 520 a, 520 b, and the engagement portion-side sections 525 a, 525 b are bent along the side grooves 520 a, 520 b and moved toward the tank body 50 a about the side grooves 520 a, 520 b. That is, the side grooves 520 a, 520 b are formed to provide the weak portions. Therefore, it is not necessary to reduce the strength of the bent portions 521, which are the corner portions between the side wall portions 52 a, 52 b and the side engagement portions 53 a, 53 b.

If an internal pressure of the tank inner space 50 c increases, the tank body 50 b receives the pressure in a direction intersecting with the tube longitudinal direction D1, as shown by an arrow Ya in FIG. 18. As a result, the bent portions 521 will receive stress from the corner edges 600 a of the projected end 600 as shown by an arrow Yb. Since the thickness of the side engagement portions 52 a, 52 b is not reduced, as the core plate 150 a shown in FIG. 30, the bent portions 521 maintain predetermined strength. Therefore, the bent portions 521 maintains durability against the stress from the corner edges 600 a, even in such a situation. Namely, it is less likely that the durability of the core plate 50 a will be reduced. Further, the side grooves 520 a, 520 b are formed on the outer surfaces of the side wall portions 52 a, 52 b at positions corresponding to the projected end 600. Therefore, the durability of the core plate 50 a against the increase in the internal pressure improves. Further, the durability of the radiator 1 improves.

The grooves 520 a, 520 b are formed on the side wall portions 52 a, 52 b as the bending base portions. Therefore, the engagement portion-side sections 525, 525 b of the side wall portions 52 a, 52 b are easily bent outwardly and moved toward the tank body 50 b.

The projected end 600 abut on the side grooves 520 a, 520 b from the inner side. Therefore, when the engagement portion-side sections 525 a, 525 b are moved toward the tank body 50 b, the projected end 600 is in contact with the inner sides of the side grooves 520 a, 520 b. As such, the engagement portion-side sections 525 a, 525 b are properly bent.

The projected end 600 projects toward the side wall portions 52 a, 52 b. Also, the contact portion of the projected end 600, which contacts the side wall portions 52 a, 52 b, protrudes toward the bottom wall portion 51 more than the other portion of the projected end 600. Therefore, the projected end 600 can easily abut on the grooves 520 a, 520 b from the inner side.

In a case that the bottom wall portion 51 does not have projections 71, if a load is applied to the bottom wall portion 51 when the engagement portion-side sections 525 a, 525 b are bent, the bottom wall portion 51 will be deformed or twisted. When the bottom wall portion 51 is deformed or twisted due to the load, the tubes 2 will receive stress and will be deformed.

In the present embodiment, since the bottom wall portion 51 has the projections 71, bending rigidity of the bottom wall portion 51 is improved. Therefore, even if the load is applied to the bottom wall portion 51, the bottom wall portion 51 will not be easily deformed.

Also, since the width W2 of the projections 71 is greater than the width W1 of the tubes 2 with respect to the tank transverse direction D3, the bending rigidity of the bottom wall portion 51 is further improved.

In the present embodiment, the sealing member 54 is provided by hardening the liquid or gel state sealing member. The sealing member 54 is in closely contact with the looped flat section 57 of the bottom wall portion 51. Therefore, even if a load is applied to the sealing member 54 from the side engagement portions 53 a, 53 b through the projected end 600 when the engagement portion-side sections 525 a, 525 b are bent, it is less likely that the sealing member 54 will be twisted or displaced. Since the sealing member 54 is maintained at a predetermined position, leakage of the engine coolant from the header tank 5 a, 5 b are reduced.

The side engagement portions 53 a, 53 b extend over the length of the side wall portions 52 a, 52 b in the tank longitudinal direction D2. Therefore, the strength of the side engagement portions 53 a, 53 b increase. As such, even when forces are applied to the side engagement portions 53 a, 53 b due to the increase in the internal pressure of the tank inner space 50 c, it is less likely that the side engagement portions 53 a, 53 b will be deformed.

Seventh Embodiment

The radiator 1 of the seventh embodiment has the similar structure as the radiator 1 of the sixth embodiment, except the structure of the core plate 50 a. As shown in FIG. 27, the core plate 50 a of the seventh embodiment has a sealing groove 800, similar to the fifth embodiment shown in FIG. 17. The sealing groove 800 is formed to have the looped flat section 57 as its bottom. The sealing member 54 is housed in the sealing groove 800.

In the present embodiment, the core plate 50 a and the tank body 50 b are fixed in the following manner. First, as shown in FIG. 28, the sealing member 54 is disposed on the looped flat section 57 of the core plate 50 a. Here, the sealing member 54 is, for example, a rubber member.

Next, as shown in FIG. 29, the tank body 50 b is placed on the core plate 50 a, such that the tank inner space 50 c is covered by the bottom wall portion 51. In this condition, the engagement portion-side sections 525 a, 525 b still extend outwardly. The side engagement portions 53 a, 53 b are substantially perpendicular to the engagement portion-side sections 525 a, 525 b.

Then, forces are applied to the engagement portion-side sections 525 a,525 b in the inward direction, as shown by arrows Ja in FIG. 29. Thus, the engagement portion-side sections 525 a, 525 b move toward the tank body 50 b about the side grooves 520 a, 520 b as the bending base portions. With this, the side engagement portions 53 a, 53 b engage with the projected end 600 of the core plate 50 b. As such, the core plate 50 a and the tank body 50 b are fixed in such a manner that the projected end 600 and the sealing member 54 are interposed between the side engagement portions 53 a, 53 b and the bottom wall portion 51.

(Modifications)

In the radiator 1 of the above embodiments, the sealing material for the sealing member 54 is hardened after being applied to the core plate 50 a. Instead, the sealing material can be hardened at the same time as being applied to the core plate 50 a. In this case, the ultraviolet rays are radiated to the sealing material while applying the sealing material to the core plate 50 a. As another example, the sealing material can be heated while being applied to the core plate 50 a.

In the above embodiments, the sealing material in the liquid or gel state is applied to the core plate 50 a after the tubes 2 are brazed to the core plate 50 a. Alternatively, the sealing material in the liquid or gel state can be applied to the projected end 600 of the core plate 50 a before the tubes 2 are brazed to the core plate 50 a.

In the sixth and seventh embodiments, the side groves 520 a, 520 b are formed on the side wall portions 52 a, 52 b as the bending base portions. Alternatively or in addition to this, the grooves 520 a, 520 b can be formed on the end wall portions 52 c, 52 d.

Also, the bending base portions may be provided by another method in various ways. For example, in the sixth and seventh embodiments, at least one aperture may be formed on the side wall portion 52 a, 52 b as the bending base portion, instead of the grooves 520 a, 520 b. Alternatively, the bending base portions may be provided by plural grooves.

In the sixth and seventh embodiments, the end wall portions 52 c, 52 d and the end engagement portions 53 c, 53 d may be formed in a similar manner as those of any one of the first to fourth embodiments, or in a similar manner as the side wall portions 52 a, 52 b and the side engagement portions 52 a, 52 b of the sixth and seventh embodiments.

In the above embodiments, the sealing member 54 in the liquid or gel sate is applied to the core plate 50 a, which is joined to the tubes 2 by brazing. However, the sealing member 54 in the liquid or gel state can be applied to a sealing surface of the core plate 50 a, which is joined to the tubes 2 by another method or material, such as by a thermoset resin, or the like.

In the above embodiments, the heat exchanger is exemplarily employed to the radiator. However, the heat exchanger to which the present invention is applied is not limited to the radiator, but may be any heat exchanger, such as an evaporator or a heater core unit, having at least one header tank 5 a, 5 b constructed of the core plate 50 a and the tank body 50 b. Also, the internal fluid is not limited to the engine coolant.

Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader term is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described. 

1. A method of manufacturing a header tank for a heat exchanger in which tubes are coupled to the header tank, the method comprising: forming a first engagement portion in a core plate by bending a portion of the core plate, the portion extending from a first wall portion of the core plate; placing a tank body, which has a substantially semi-tubular shape and an opening, relative to a base portion of the core plate such that the opening is covered by the base portion and a tank inner space is provided between the tank body and the base portion; and moving the first wall portion toward the tank body such that the first engagement portion is engaged with the tank body.
 2. The method according to claim 1, further comprising: pre-bending the first wall portion relative to a plane of the base portion by a predetermined angle, before the placing of the tank body, wherein in the moving of the first wall portion, the first wall portion is moved toward the tank body from a pre-bent condition formed by the pre-bending.
 3. The method according to claim 1, wherein in the moving of the first wall portion, an engagement portion-side section of the first wall portion is moved toward the tank body about a bending axis, the bending axis being included within the first wall portion, the engagement portion-side section being a portion of the first wall portion between the bending axis and the first engagement portion.
 4. The method according to claim 3, further comprising: pre-bending the engagement portion-side section relative to a remaining section of the first wall portion along the bending axis in an outward direction before the placing of the tank body, wherein in the moving of the first wall portion, the engagement portion-side section is moved from a pre-bent condition formed by the pre-bending toward the tank body.
 5. The method according to claim 1, wherein in the moving of the first wall portion, the first wall portion is moved up to a position where an outer surface of the first wall portion forms an angle equal to or greater than 90 degrees relative to a plane of the base portion.
 6. The method according to claim 1, wherein the moving of the first wall portion includes engaging the first engagement portion with the tank body such that the first engagement portion forms an acute angle with the first wall portion.
 7. The method according to claim 1, further comprising: setting a sealing member to at least one of the core plate and the tank body before the placing of the tank body, wherein the placing of the tank body includes arranging the tank body relative to the core plate such that the sealing member is disposed between the tank body and the core plate.
 8. The method according to claim 7, wherein the setting of the sealing member includes applying a sealing material in a state of at least one of gel and liquid to at least one of the core plate and the tank body and hardening the sealing material thereon.
 9. The method according to claim 1, wherein in the moving of the first wall portion, the first wall portion is moved about a bending axis, the bending axis being parallel to a longitudinal axis of the tank body.
 10. The method according to claim 9, further comprising: bending a second wall portion of the core plate across the longitudinal axis of the tank body before the placing of the tank body, the second wall portion being separated from the first wall portion; and bending a second engagement portion that extends from the second wall portion toward the tank body to engage with the tank body after the placing of the tank body.
 11. A heat exchanger comprising: a plurality of tubes; and the header tank manufactured by the method according to claim 1, wherein the plurality of tubes are coupled to the core plate.
 12. The heat exchanger according to claim 11, wherein the core plate includes weak portions, at which strength of the core plate is reduced less than other portions, along a bending axis of the first wall portion along which the first wall portion is moved.
 13. The heat exchanger according to claim 12, wherein the bending axis is included within the first wall portion.
 14. The heat exchanger according to claim 12, wherein the weak portion is provided by a groove.
 15. The heat exchanger according to claim 12, wherein the weak portion is provided by one of a plurality of openings and a plurality of recesses disposed along the bending axis.
 16. The heat exchanger according to claim 11, wherein the first wall portion extends from a lengthwise edge of the base portion and the first engagement portion extends from the first wall portion, the lengthwise edge being parallel to a longitudinal axis of the tank body, and the core plate further includes a second wall portion and a second engagement portion, the second wall portion extending from a widthwise edge of the base portion, the widthwise edge being across the longitudinal axis of the tank body, the second engagement portion extending from the second wall portion and is engaged with the tank body.
 17. The heat exchanger according to claim 16, wherein the core plate further includes a support wall portion that extends from the lengthwise edge of the base portion, the support wall portion is separated from the first wall portion and is configured to support the second wall portion.
 18. The heat exchanger according to claim 16, wherein the first engagement portion extends over a lengthwise end of the first wall portion, the lengthwise edge being parallel to the longitudinal axis of the tank body.
 19. The heat exchanger according to claim 13, wherein the tank body includes a contact portion that contacts the bending axis of the core plate from an inner side of the core plate.
 20. The heat exchanger according to claim 19, wherein the contact portion projects toward the bending axis and has a surface opposed to the base portion, and the surface of the contact portion partly protrudes toward the base portion.
 21. The heat exchanger according to claim 11, wherein the base portion includes a plurality of holes to which the tubes are coupled, and the base portion further includes a plurality of projections projecting in a direction opposite to the tank body, the plurality of projections are disposed between the adjacent holes.
 22. The heat exchanger according to claim 21, wherein each of the projections has a width greater than a width of the tubes with respect to a direction perpendicular to a longitudinal axis of the tank body.
 23. The heat exchanger according to claim 11, further comprising: a sealing member disposed between the tank body and the base portion of the core plate in an elastically deformed condition to seal between the tank body and the core plate.
 24. The heat exchanger according to claim 23, wherein the tank body includes a projected end on a perimeter of the opening, the core plate includes a sealing surface on the periphery of the tubes, and the sealing member is disposed between the projected end of the tank body and the sealing surface of the core plate.
 25. The heat exchanger according to claim 24, wherein the core plate includes a sealing groove, and the sealing surface is provided by a bottom of the sealing groove, and the sealing member is disposed in the sealing groove. 